Marine litter and microplastics

8. Conclusions

The main gaps in knowledge that have been identified are:

• There is a need to identify and develop global environmental standards, as well as broadly applicable indicators, with which to benchmark these standards.
• There is a need for better understanding of the dynamics of compounds that are Persistant, Bioaccumulative and Toxic (PBTs) in relation with micro-plastics in the marine environment.
• The quantities of plastics entering the oceans are still largely unknown, and methods need to be developed to measure and to limit that input.

A global assessment of micro-plastics could be integrated with already existing programs such as the UN Assessment and the Transboundary Waters Assessment Programme (TWAP). There just needs to be a set of standardized methods to latch on to these existing initiatives, and the sampling methods developed by NOAA could be a useful tool for that.

The main conclusion is that there is still very limited information on micro-plastics in the marine environment. We do not know how much of it makes its way to the oceans and how it behaves once it is in the oceans, both in terms of movement in the ocean and in terms of degradation, fragmentation, and modification of properties due to weathering. In addition, very little is known on the degree to which micro plastics transport contaminants and on the physical and chemical effects plastic fragments on the ecosystem.

There is also a need for an assessment to follow on from UNEP’s efforts, to collate the available scientific information and make recommendations that will be of use to the wide variety of policy, industry and societal organisations that have responsibility in this area. This assessment should take into account the overall marine debris and solid waste management problem. More...